/**
 * WorldCreator.java
 *
 * @author David Tran
 * @version 1.1
 */

package world;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.FileReader;
import java.util.StringTokenizer;
import java.util.zip.DataFormatException;
import java.io.FileNotFoundException;
import java.io.File;
import javax.swing.JFileChooser;
import java.net.URL;

import background.*;

/**
 * A WorldCreator creates a World with particular Background objects 
 * whose description and location are given in a specified file,
 * where each line of data is of the following format: <br><br>
 * 
 *     backgroundName xCoordinate yCoordinate width height <br><br>
 *
 * where backgroundName is the predetermined name refering to some background 
 * (e.g. Vertical-Road, Lake, House)<br>
 * where xCoordinate refers to the leftmost x-coordinate of the background<br>
 * where yCoordinate refers to the uppermost y-coordinate of the background<br>
 * where width refers to the maximum horizontal distance from the xCoordinate
 *  of the background object<br>
 * where height refers to the maximum vertical distance from the yCoordinate
 *  of the background object<br><br>
 */
public class WorldCreator  {
    
    /** Name of a file to use if a good file name is not supplied as a parameter.
     *Generally the best place to put this file is in the same package (directory)
     *as the class which is processing it; in this case, the same directory as
     *WorldCreator.java.
     */
    public static final String defaultFilename = "World.txt";

    /**
     * Modifies a World with Background objects taken from a file.
     *
     * @return - World instance of a World object, with the modifed background objects.
     */
    public static World modifyWorld(World w) {
        return modifyWorld(null, w);
    }
 
    /**
     * Modifies a currently existing World by adding Background objects 
     * specified in the fileName.
     * If the world does not exist (i.e. w is null), a new World is created 
     * and returned, in which the Background objects will be added.
     *
     * @param fileName the name of the file describing the background objects;
     *  if the fileName is null or empty or if the file cannot be found,
     *  a built-in default is tried; if that fails,
     *  the user sees a File Chooser dialog and can browse to the desired file.
     * @param w the currently existing World
     * @return World - instance of a World object if file was read successfully,
     * otherwise null
     */
    public static World modifyWorld(String fileName, World w) {
        
        //The starter code in the method can be removed for Step 1.
        //For Step 2, you should put it back in.
        if (w == null) {
            w = new World();
        }
        if (fileName == null || fileName.equals("")) {
            fileName = defaultFilename;
        }
        java.io.File f = getFile(fileName); //make sure there is such a file
        
        //At this point, if f is not null, then the file exists.
        String fullAbsolutePath = null;
        if (f != null) {
            fullAbsolutePath = f.getAbsolutePath();
            assert fullAbsolutePath != null;
            System.out.println("Using background text file " + fullAbsolutePath);
        } else{
            System.out.println("Tried and tried, but STILL could not open a file," + 
                " not even " + fileName);
        }
        //If fullAbsolutePath is not null, you should be able to create a stream on it.
        //You might also use f directly for creating the stream.
        //Starter code for the method ends here...
    }

    /** [DO include in the starter code]
     * Displays a dialog box to choose the file, if the requested one doesn't exist.
     * @return the file that the user selected or null if user selected cancel
     */
    private static File getFile () {
        return getFile(null);
    }
    /** Locate the requested file, if possible, or a file
     * selected by the user.
     * For best results, place the file in the same directory as this class,
     *  or in some other package used by the application.
     * Displays a dialog box to choose the file, if the one requested doesn't exist
     * 
     * @return the file that was requested,
      or one the user selected, or null if user selected cancel
     */
    private static File getFile(String requestedFilename) {
        String startingPath;
        if (requestedFilename != null) {
            //see if the file exists
            java.io.File requestedFile = new File(requestedFilename);
            if (requestedFile.exists() && requestedFile.isFile()) {
                return requestedFile;
            }        
            //The file wasn't found via its original requested name, in the default location.
            //Look for it on the class path
            java.net.URL fileURL = ClassLoader.getSystemResource(requestedFilename);
            if (fileURL != null) {
                //found it on the class path
                String fullName = fileURL.getPath();
                requestedFile = new File(fullName);
                assert requestedFile.exists();
                if (requestedFile.isFile()) {
                    return requestedFile;
                }
            }
        }
        //Let user browse for it, starting from the directory of the current class
        Class wcc = WorldCreator.class;
        String myClassName = wcc.getName();
        String myClassFilename = myClassName.replace('.', '/');
        myClassFilename += ".class";
        java.net.URL classURL = ClassLoader.getSystemResource(myClassFilename);
        if (classURL != null) {
            startingPath = classURL.getPath();
        } else {
            startingPath = "."; //last resort
        }
            
        JFileChooser fc = new JFileChooser(startingPath);
        int retVal = fc.showOpenDialog(null);
        fc.requestFocus();

        if (retVal == JFileChooser.APPROVE_OPTION) {
            File file = fc.getSelectedFile();
            assert file != null && file.exists();
            if (file.isFile()) {
                return file;
            }
        }
        //totally out of luck
        return null;
    }
    
}